To think of deliberately interfering in the Earth system will undoubtedly be alarming to some. But so will an Anthropocene deprived of such deliberation. A way to try and split the difference has been propounded by a group of Earth-system scientists inspired by (and including) Dr Crutzen under the banner of “planetary boundaries”. The planetary-boundaries group, which published a sort of manifesto in 2009, argues for increased restraint and, where necessary, direct intervention aimed at bringing all sorts of things in the Earth system, from the alkalinity of the oceans to the rate of phosphate run-off from the land, close to the conditions pertaining in the Holocene. Carbon-dioxide levels, the researchers recommend, should be brought back from whatever they peak at to a level a little higher than the Holocene’s and a little lower than today’s.

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The Earth’s history shows that the planet can indeed tip from one state to another, amplifying the sometimes modest changes which trigger the transition. The nightmare would be a flip to some permanently altered state much further from the Holocene than things are today: a hotter world with much less productive oceans, for example. Such things cannot be ruled out. On the other hand, the invocation of poorly defined tipping points is a well worn rhetorical trick for stirring the fears of people unperturbed by current, relatively modest, changes.

In general, the goal of staying at or returning close to Holocene conditions seems judicious. It remains to be seen if it is practical. The Holocene never supported a civilisation of 10 billion reasonably rich people, as the Anthropocene must seek to do, and there is no proof that such a population can fit into a planetary pot so circumscribed. So it may be that a “good Anthropocene”, stable and productive for humans and other species they rely on, is one in which some aspects of the Earth system’s behaviour are lastingly changed. For example, the Holocene would, without human intervention, have eventually come to an end in a new ice age. Keeping the Anthropocene free of ice ages will probably strike most people as a good idea.

… Currently, there are two paradigms of agriculture being widely promoted: local and organic systems versus globalized and industrialized agriculture. Each has fervent followers and critics. Genuine discourse has broken down: You’re either with Michael Pollan or you’re with Monsanto. But neither of these paradigms, standing alone, can fully meet our needs.

Organic agriculture teaches us important lessons about soils, nutrients and pest management. And local agriculture connects people back to their food system. Unfortunately, certified organic food provides less than 1 percent of the world’s calories, mostly to the wealthy. It is hard to imagine organic farming scaling up to feed 9 billion.

Globalized and industrialized agriculture have benefits of economic scalability, high output and low labor demands. Overall, the Green Revolution has been a huge success. Without it, billions of people would have starved. However, these successes have come with tremendous environmental and social costs, which cannot be sustained.

Rather than voting for just one solution, we need a third way to solve the crisis. Let’s take ideas from both sides, creating new, hybrid solutions that boost production, conserve resources and build a more sustainable and scalable agriculture.

There are many promising avenues to pursue: precision agriculture, mixed with high-output composting and organic soil remedies; drip irrigation, plus buffer strips to reduce erosion and pollution; and new crop varieties that reduce water and fertilizer demand. In this context, the careful use of genetically modified crops may be appropriate, after careful public review.

A new “third way” for agriculture is not only possible, it is necessary. Let’s start by ditching the rhetoric, and start bridging the old divides. Our problems are huge, and they will require everyone at the table, working together toward solutions.

Croplands and pastures cover about a 1/3 of the Earth’s ice free surface. Foley et al in their PNAS commentary Our share of the planetary pie illustrate the uses of this agricultural production. Their map shows the percentage of crop NPP used to produce food that humans consume directly (blue) or indirectly in processed products (orange-red). The majority of the nonfood portion is feed for livestock, but also includes fiber or luxury crops, such as cotton and coffee. Note the differences between agriculture is rich (feed for livestock) and poor countries (food).

Is the home of polar bears, seals and Inuit communities already doomed? asks Jon Foley in Tipping Points in the Tundra a recent commentary Science. According to him, several recent sources of evidence show that feedback mechanisms seem to be kicking into high gear as the Arctic warms up. Temperature data illustrate, for example, that from the 1960’s to the 1980’s, the Arctic warmed by 0.15 degrees Celsius per decade, but since then the warming has been nearly 0.3 to 0.4 degrees per decade.

Recent evidence comes from Terry Chapin and his co-workers who have analyzed Arctic data on surface temperature, cloud cover, energy exchange, albedo, and changes in snow cover and vegetation. They concluded that the recent changes in the length of the snow-free season have triggered a set of interlinked feedbacks that will amplify future rates of summer warming. One of these feedbacks relate to that the snowmelt has advanced by around 2.5 days per decade which has lead to an increase in the amount of energy that is absorbed and transferred to the atmosphere. The resulting regional increase in temperature is estimated to be comparable (per unit area) to the global atmospheric heating that is projected from a doubling of CO2 levels in the atmosphere.

Chapin et al. also analyses the role of vegetation change for triggering positive feedbacks. Tall shrublands have increased rapidly in the surrounding region of the Arctic. Tree lines have also moved further north. Although the estimated contributions these have on warming were found to be small, the authors expect that they will continue to increase disproportionally in the future.